More than 1.3 million new cases of invasive cancer are expected to be diagnosed in the United States during 1997 (Parker et al. CA Cancer J. Clin. 47:5 (1997); this estimate does not include carcinoma in situ (except in the bladder), nor does it include basal and squamous cell cancers of the skin). Among women, it is estimated that the three most commonly diagnosed cancers in 1997 will be cancers of the breast, lung and bronchus, and colon and rectum. Breast cancer alone will account for 30% of new cancer cases in 1997. Among men, the most common cancers in 1997 will be cancers of the prostate, lung and bronchus, and colon and rectum, with prostate being the leading cancer site and accounting for 43% of new cancer cases.
Prostate cancer accounts for 36% of all male cancers and 13% of male cancer-related deaths (surpassed only by lung cancer). It is estimated that approximately 334,500 new cases of prostate cancer and 41,800 prostate cancer-related deaths will occur in the United States in 1997. Incidence rates of prostate cancer have increased over the past 35 years. Parker et al. CA Cancer J. Clin. 47:5 (1997). Screening for prostate cancer has traditionally relied on digital rectal screening. Transrectal ultrasound and measurement of prostate-specific antigen (PSA) in the blood have also recently become available to aid in the diagnosis of prostate cancer. See, e.g., Friedman et al., Lancet 337:1526 (1991); Littrup, Cancer 74 (7 Suppl):2016. However, the cost, relatively low specificity, and invasiveness of rectal imaging techniques precludes these from use in routine or large-scale screening for prostate cancer. Additionally, the effectiveness of such techniques are non-specific and depend on the skill and experience of the examiner. Waterhouse and Resnick, J. Urol. 141:233 (1989); Waterhouse and Resnick, Urology, 36:18 (1990).
Benign Prostate Hypertrophy (BPH) is a common condition in men over the age of 50, and occurs in the majority of men over the age of 80. BPH and prostate cancer may occur simultaneously in a subject.
It is estimated that in 1997 breast cancer will account for 30 percent of new cancer cases, with about 180,200 new cases diagnosed. Parker et al. CA Cancer J. Clin. 47:5 (1997). Diagnosis of breast cancer typically depends on physical examination of the breast and/or routine mammography, with subsequent ultrasound and/or biopsy as indicated.
Due to the known association of PSA with diseases such as BPH and prostate and breast cancers, and the high incidence of such diseases, it would be advantageous to develop effective and convenient methods of screening for the presence of cancer.